Guided missile



June 27, 1950 E. c. SPARKS; JR.. TAL 2512.593

GUIDED MIssILE Y Filed July 2, 1946 3 Sheets-Sh'eet 1 /3 /7 .f ,f RADAR ANT.

4/ Qf/ @d y Q/ vf 50 ELEv.| IAZTM. )(85 f l I [60 56`l ELEV SPACE m REFER-GYR0 75 Ui J/f Hgng, a? sPAcE REFER GYRo /23 w50? L STABLE An.. AND i I June 27 1950 E. c. SPARKS, JR., ETAL 2,512,693

GUIDED MISSILE Filed July 2, 1946 3 Sheets-Sheet 2 FEELER PowER 2o Tom/www1@ SYSTEM SUPPLY RADAR JUNCTION SELECTOR l Box `40 25 g'l ELevA-ron 7 REF 1 sERvo7 f 75 UP ELEVATOR PROPORTIONAL ROLL TRIM MOTOR f vv v vr. 40s'. )l2 29 STABLE .f z o vent sYRo wvQ/wbO/r. Earl G." Sparks Jn F'g'3 Maui-#on B. Taysior WWW .Furie 27 1950 E. c. SARKS, JR., Er'AL 2,512,693

GUIDED MISSILE Filed July?, 194e z 'sheets-sheet s Y ARADAR r2.3 ANT. kan

j/ *UT 28s 2*/25O\,ELEV. AZIMI ll 12'? www .i Emi C. Sparks,dr.

ouion "WWW Patented June 27,v 1950 GUIDED MSSILE Earl C. Sparks, Jr., Cranston, R.' I., and Moulton B. Taylor, Huntingdon Valley,'l?a.

.Application'uly 2, 1946, Serial No.- 680,905

21 Claims.

This invention lrelates t guided missiles, v'and more `particularly, this invention relates to guided missiles capable of computing andV traveling along an intercept course to apreselecte'd target.

A primary object ofthis'invention is to provide a, missile with automatic devices to compute and control said missile along an intercept course to a preselected target.

Another object is to provide a"guided=mis`sile with means of selecting a particular object as the target.

A further object is to provide afguided missile that requires no remote control for its operation after the target selectionhas been made.

Other objects and advantages of this invention will be apparent lfrom the following description.

Reference is now made to theaccompanying 'rawings wherein corresponding numbers refer to corresponding parts and in which:

Fig. 1 is a View of the missile, towing craft, and target after the missile 'has been released from the tow cable;

Fig. 2' is a block diagram of' the control unit radar, and antenna. mechanism of the preferred embodiment;

Fig. 3 is a schematic diagram ofthe control units and. circuits including an isometric view of the l. antenna mechanism;

Figli is a sectional view of a three-wire conductortow cable;

ligp is an isometric presentationof the ntercept computation problem in the vertical plane;

Fig.. Sanrisometric presentation ofthe in- .tercept 'computation problem in the horizontal plane;

V4Fig. 7 is `an isometric ypresentation of the in- 4tercept computation problem. inAv both horizontal andverticallplanes;

:Fig is a sectional view showingfthe features vof a gyroscope utilized by this invention; and

.Fig 9 is la block diagram of an alternatearrangement of the proposed invention.

The invention consists -of a radar set andwafppropriete-control equipment cooperating to guide an airborne .missile along -anintercepty course to i the pointof yimpact with a selected target. `The radar '.setselected fornse in this invention must `provide signals indicative of the relative position of the selected target with respect to the axis of the antenna in addition to thecustomary requirements Vfamiliarto those skilled in thel art. 4The control equipment includes cageable Ygyro- (Granted under the act Yof March 3, 1883, as amended April 30, 1928; 370 O. G. 757) CII to send a final audioifrequency voltage along scopes, servomotors, pulleys and .controly cables,

a suitable mechanical system 4Vcooperating with slewing motors to control ran -antennain'both azimuth and elevation, @an audio frequency-operated relay selector, .anautomatic ycontrol` device as described in thefapplicationJSerialoNo.

592,627, series of 1935 issuedto MoultonB..Tay

lor, co-inventory herein, now'PatentNo.f2;4-32,548 issued. December. 16, 1947, :athree-conductor tow `icable, and an electrical intelligence f combining vdevice hereinafter to be referred to asa mixer.

Prior to the application oithis invention-for thegpurpose of g-uidingrthe. missile `along .an interceptcourseto a targetpthe. missile istowed by the three-conductor towcable .and a parent aircraft. During the towing period, theradar equipment is tuned from the parenty aircraft-,by

the conductor of the tow cable' to operate a Single relay that, vfirst, completes the'circuits to allow the invention 5to compute the' intercept course to the targerrandthus' guide themissile accordingly; second, `"disengages' the automaticH control device; and nally, vdisconnects the ltow cable from the missile.

Fig. 1l showsl the1-missile= immediately afterthe 'tow cable has been disconnected from the missile,

thus=- allowing the parent craft to return Vtota safe operating area.

Included in the procedurev of computingl the interceptk course is theapplication of-direct-'current -voltages toslewing "motors which Aaresuitably geared to the antenna/mounting andthuscontrol the positioningof the antenna beam. These direct-current voltages areV outputs' from aV sensing 'circuit vprovided in the radarequipment and are of the polarity and'amplitudeindicative f'the direction and amount that thetarget deviates angularly from aI reference vaxis oftheY antenna beam. The elementsherein considered cooperate vso as to cause theaxisof the'antenna beamte SCOpeS.

3 continually reposition itself to bear on the selected target. Flexible cabling operating over suitable pulleys serve to link the described antenna, movements to produce a displacement of the gyroscopic orices of the yaw and pitch controlling gyroscopes as necessary. Direct-current output Voltagesappearing as a function of the relative orifice displacement in the gyroscopes control aileron and elevator servomotors which in turn impart a movement to the rudder, elevators and ailerons of the missile, thereby positioning the missile on an intercept course. A follow-up system returns the gyroscopic orifices to a, neutral position about which they remain until again demanded to recorrect the missile position due tov changes in relative azimuth and elevation of the target.

In the embodiment shown in the accompanying drawings, and in particular Fig. 2 wherein the solid connecting lines indicate electrical connections and the broken connecting lines indicate mechanical linkages, the invention consists generally of -a radar system indicated generally at I3 and the necessary control units and circuits, and

vin addition, an antenna I1 with suitable mountings to allow control in both azimuth and elevation. Separate servomotors Y50 and 83 provide the necessary control of the antenna in the two directions. Gyroscopes 56, 81, and |05 and accompanying roll trim motors |02, elevator servomotors 60, and aileron servomotors I|0 aifect the control airfoils 15, ||8, and |23 of the missile to keep the missile on the intercept course, utilizing the radar-controlled antenna movements to provide fa properly proportioned displacement of theY orifices in the gyroscopes. A suitable follow-up system is employed to neutralize the gyroscopes and reestablish equilibrium in the system. The gyroscopes 81 and 56 controlling yaW and pitch respectively are reverse-connected so that an error signal introduced in either of the gyroscopes by virtue of an angular displacement of the missile will provide signals to therespective servomotors producing a movement of the control airfoils so as to cause the missile to respond in such manner as to introduce further error'in the gyro- Reverse connected as used here, indicates that the external Wires 60 and 10 from space reference gyro 56 and the external wires 98V and 99 from the space reference gyro 81 are reversed in polarity to gyro output terminals so that they produce a motion of the airioil in response to an angular displacement of the aircraft and uncaged gyro that is opposite the motion of an airfoil in response to the same angular displacement of the aircraft in normal automatic ,pilot operation; i. e., in normal automatic pilot operation the electrical or mechanical connection between an uncaged gyro and an airfoil is such that an angular displacement of the aircraft to the right (or up in pitch axis) causes a gyro error Which in turn, due to the polarity of wires from gyro to servos, produces an airfoil motion that causes the original angular displacement of the aircraft to be decreased and removed by angular motion of the aircraft to the left (or down). In the operation of an uncaged gyro and the airfoil as used in this application, the electrical connection between the uncaged gyro and the airfoil is such that an angular displacement of the aircraft to the right (or up in pitch axis) causes a gyro error which, in turn, dueto the polarity of Wires from gyro to servo, produces an airfoil motion that causes the original angular'displace-L ment of the aircraft to be increased by additional angular motion to theyright (up in pitch axis).

The purpose of introducing further error in the gyroscopes is the basic way of obtaining the lead angle necessary to produce a nevigational or intercept course instead of a homing course. In producing further error. due to an angular devia- .tion of the aircraft, the gyros have now caused the aircraft to move ahead of the target. This further error introduced by the gyroscopes being reversed connected now has to be removed by the target seeker moving back on the target till a proper equilibrium has been reached between the gyros tendency to produce this further error and the target seekers ability to follow the target and remove the gyro error signal. In the normal sequence of events in the operation after release of the towed aircraft the gyro would remain caged until there was no chance of losing return radar signal and at this time the AVC voltage would uncage the gyro. This would leave the antenna, in full control to remove the uncaged gyro ability to add on an ever increasing turn. The antenna angular motion with caged gyro produces straight homing course. With an uncaged gyro reversed connected to add error angle, the antenna, gyro and aircraft produces an intercept course with proper lead angle when in equilibrium and continues to correct to the course. The characteristics thus established in the gyroscopes provide a basis for the devices ability to guide the missile along the automatically computed intercept course to the target. A third gyroscope |05 connected in the conventional manner is provided for roll stabilization. The servomotors controlled by the gyroscopes may be electrically powered, or they may be vvacuum or hydraulically operated with proper electric valves to control clockwise or counterclockwise rotation as desired.

The operations of the control system while the missile is being towed into itsfeffective operating range, which is limited only by inherent range limiting characteristics of the radar equipment employed, is dependent upon an automatic control system which is put in operation prior to take-olf and disconnected by the audio-frequency tow line voltage energizing the appropriate relay contained in the selector.

In the embodiment illustrated .by Fig. 3, the axis 1 of the parabolic reflector 8 is seen to be mounted at a small angle with respect to the foreand-aft reference axis 9. The parabolic reflector 8 Vrevolves about the axis 9 driven by the drive motor I0 through gear II meshing with gear I2 which is rigidly xed to the parabolic reector 8. This revolution will cause the axis 1 of the parabola to generate a cone of revolution. Characteristics of the parabolic reflector 8 cause the radio-frequency energy developed by the radar equipment I3 to radiate and the reflected 'radiofrequency energy to be detected only along a very narrow ibeam. The combined effect of the narrow beam and the revolution is to produce a field pattern that is conicalfin shape. Voltage indicating the position of the antenna beam in its cone of revolution,k i. e., up, down, right, or left, and other necessary control voltages complete their link between the antenna system and the radar equipment I3 via the multi-conductor cable I6. The radio-frequency` energy is conveyed to and from the radar equipment I3 Iby means of the coaxial cable I4 and the rigid coaxial conductor I5. rIhe radar equipment I3 receives the proper operating voltages from a sepansiosa "1n-ulti; conductor cableZ 2V:where'these-voltages are `distributed One series Aofi these voltages.E appears onfl-tlie \single-'concluctor4 cables i23, 24, 7.5- and '.25. Theamplitudes of -these voltages. are proportional :..totlie degree of displacement fof-f theI target from ftl-iefoiei-and-aftf reference-axislS. A secondise- *riesf' 'ffthe- `aforementioned Volta-'ges isi 'impressed fon the'multieconductorfcable21 Vtoa mixer 2t "Where they are prop erly 1 combined -and trans- 'lniitted totheparent aircraft along one conductor 2 9 ofl -the tovvlineZ. Referring' to Fig. A, which a sectional lview of ythei towline 32, the outer "casing 33 ireceivesf the fload produced .bytowing and lalsofhouses the. three single conductor. cables 34, 35 an'de'land Itheir.respective conductorsg, 530 1an'd3l. IAS described Aabove, direct-current A'voltages properly combined-are impressed on yconducten-29 "for transmission?ltol the iparent aircraft. Similarly,l conductor 136 is used forr transmission r ofA the video; trigger, andgate output ofthe radar lfcon'du'ctorf cables 22 and :2l-and the junction box '2L Conductortis. used for transmission of ten "different audio'irequencies generated .by 'an audio -frefn'iency-oscillatorin'y the lparent plane to a se- "lectori Aipanelof ten-switches Ain the parent aircraft provide'selection ofI a desired audio fre- `'quency to '--be :generated 'by' the audiol frequency oscillator. -The `vvarious audio frequencies 1 introe duced into" the selectorl are fed into frequency selective circuits -suitablycoupled tofa series o- 'tenrelays, each circuit being tuned to one of the tenivaudiofrequen'cies and so coupled as to op- -`era-tea'single'relayinresponse to an audiovin- -put-of-theappropriate frequency. The contacts `'of'i the various-relay vcircuits are connected to the radar syste-m through the multi-conductor cables "4 I' andf22andthejunction boxZI to perform var- '-iQusOperating fand l'tuning adjustments. One audioffrequencyand its associated relay circuit is reservedffor disengaging the automatic control system-"42; arming the missile,-and nally discon- "necting the"-towcable itself.

An Voutput voltage proportional to the ampli- "tudeiof a lreceivedrradai"echosignal commonly 'referredtoas auto-maticvolume control voltage 'or-simplyAVC'voltageisLimpressed on the elecltr-ic`al"uncaging/ devices '6 I and 92 ythroughl multi- 'conductor cablegfjunction Ibox 2I and the con- `du'ctorsw'lS Vandrlldand' is thus utilized to automaticallyuncage the space reference gyroscopes Li'andl. v

The trunnion'i and a similar-trunnion (not shown) on" the opposite side ofY the antenna as.-

senrblyrallows rotation in thevertical plane'of thepa'rabolic reector' aboutanaxis-4Q. This rotation is controlledby the voltages appearing` "parabolicf reflector S'fabout'the `axis lgg'andfco'nnections are made to the inotori in such-aman- -nerl-as'to cause rotationrof the parabolic reflectori-8' 4in aVi fdirec'tion 'to align the-target' Withrfthe 5 fiore-and-af't reference aXisS. yItf'is tobe under- Astood Yatlthis" timeI that' themechani'cal vfeatures of i the antenna-mounting as vdescriloed'donoterestrict -f this invention f -to that -Yspecic type fof mounting.l L'Aixed tolti-ie gear segment H52 @and l adjustable in position radiallyis a freeerotating pulley'i over which is run suitable cabling @M-i542 kne Side 'ofthe cablelillv connectsiwith the :drum '55`lof l'thegyroscope 4Etiafter passing over -a "suitable pulley systeml," While theother l5 -side of thecalble" 5ft passes overa suitablepulley system'-58 tof-the -arml ofI `an elevator serve-*60. "iT-he gyros'cope has a suitable suctionffconnec- 'i tiontfl and battery connection 6 5; the batteryicircuit being fronif the battery connection'v through toIk they battery Sfwith itsl proper `groundconnection. The-gyroscope acXmu'tted'Ipick-ol contacts t of gyroscopekit are connected bythe conductors "E5-*5lA and"fllitov terminals `'I I and] 2- Vrespective'elyvof ztneservofti. 'The armle `.and cablata provide thefl'loW-up' systemf'for the gfyroscope-E. #As-ec- "ond cable 'le passing over a suitable pulleyflll .con-

I trols the action of the; elevator l5.

#Direction-al ontrol of 'the antenna 'int-azimuth r is provided by the'action of the .antennaassenibly Inountingtable' T9 which rotates in theI horizontal plane about anlaxis. The table'IS is provided ff'with gearing la I` alonga i segment f of its Y periphery l"that is inefshed Withf-the pinionfvgearB 82. H'Ihe ro- `*tation about -axis ill is` controlledlby the .voltages i-appearinglon1 conductors 1125 and 216, vvhic'hare lproportienalto '-the *deviation of the targetffin thehorizontal-rplane from the fore-andaitref- -erence1axisli-Therelative amplitudes of'these 40 voltages v"determine the f direction f of i rotation-Iof -the Aserv'omotorv4 83' to -`which theyeare' connected. "Theshaft of ithe `servomotor'ilis rigidly xedito the pinionf-gear82, andV hence; controlling offthe rotation of -the servornotor 83 Awill control vthe l"*rotation-oftlxe parabolic reflectorf about '-'the *Verticaliairis 80. -`Afxed tothe tableV'IS andiadfjus'table -in YYpositionv radially iis a rfree-rotating pulley' 8:3 over which is run suitable cabling 385-85. @ne side ofthe cable S5" connects with l"thefdrumfi1of the gyroscope B'Lfwhereas the lother 4side lofthe'cable passes over suitable k2pi`illeys88 and189 to the 90 yokeQII of a propori tional roll Itrim motor 9|. The gyroscope 81- has ka-suitable suction'connection 95 and battery con- -nection"9, the'battery circuit being from the battery connectionSthrough the conductor 91 fandLthemain on-oiswitch 6l tolthe battery: 68.

. Thee gyroscopic-actuated pick-o contacts of gyroscope'-f81fare connected by the conductors 98 .60 and/99 to'terminals IIN) and lill respectively of the roll trim motor` SI. 'One arm of the yoke 30 vand -ca'bleBS-.provides thefollow-.up systernior the l;,gyro'scope `8l. Contained on lthe other arm .of thesyoke- S lis apulley iIZ overlwhich'islpassed thelcabling IIlS-IUBZ-*one-side' m3 being con- '.necte'd to the drum Igll' of a verticallystablegyroscope I S5, and the other side I03vbeing connected .to the arm I09 ofthe servo I I 0 after passing over Ya suitable pulley III. vAsuction connection' I |12 Iis providedfor -the-gyroscope |05 as is a battery lconnector |01 to the battery connection |08. The

gyroscopic-actuated pick-01T contacts of Ythe gyroscope vlIlfare connected 'by the conductors iH3 and II4 -to terminals -II5 andv I IIiof the aileron 75 servomoton Il 0. There are threecable-connect passing over1suitable pulleys ||9 and |20.k Fon` clarity, only one aileron has been shown, al-

though an oppositely acting left aileron is of course provided. A cable |2| also connected to the arm |09 leads over a suitable pulley'systeml |22 to control the rudder |23.

In placing the device into use, a conventional systeminspection is made prior vto take-offy at which time the main on-oif switch 61 is turned on, and the automatic control or feeler system 42 put into operation to control the missile until its point of release. YWhen the missile is airborne and being towed by the parent .craft by the three-conductor tow cable 32, the radar operator aboard the parent craft performs the tuning and adjustment of the missile-borne radar equipment I3. Conductors 29 and 30 contained in the tow cable 32 provide the radar operator with suicient information, i. e., video response, gates, trigger pulses, test voltages, etc., to enable him to perform these adjustments. is first combined in the mixer 28 in suitable form for simultaneous transmission along the conductors 29 and 30 and then decomposed in the parent craft to present the information in itsoriginal form. Remote tuning and adjustment is made `possible by the ten selector switches, the associated audio frequency generators in the parent craft, the three-conductor tow cable 32, and the selector 40 and mixer 28 in the missile; the operation having been previously described in this specification. Upon selection of an appropriate target, the pilot of the parent craft is instructed to ily a dead-reckoning intecept course to the target; and the radar operator positions that target by controlling the selector circuits of the radar equipment |3 in the missile. The antenna system of the radar equipment I3 now is able to provide sensing voltages on the conductors 23,

. 24, 25 and 26 that are indicative of the selected targets position with respect to the fore-andaft reference axis 9 9. yA final audio voltage is sent to selector 40 by operation of the proper switch in the parent craft, and a circuit which is thereby completed disengages the automatic control system 42, arms the missile, and disconnects the tow cable 32. At the time of release, the antenna bears on the target and the missible on a course as judged previously by the pilot of the parent craft; and the components of the invention are in a state of equilibrium. This equlibrium will not be disturbed until an angular displacementof theA target with respect to the fore-and-aft reference axis 9-9 occurs of suflicient magnitude to be detected by the antenna and radar sensing circuits. The radar equipment |3 detecting the selected target now provides asumcient AVC voltage through conductors 43 and 44 to the uncaging elements 6| and 92 allowing the space reference gyroscopes 56 and 81 to uncage. The elevation .control ofthe missile will be considered at this time, the azimuth control to be considered later.

Referring to Fig. 5, at the point of release of the missile from the parent craft |30, the antenna and radar sensing circuits are not able to detect the angular displacement of the target as it moves vertically from its starting point |40 until the missile has reached Va point |3| along its path |30-,|40, whereupon the target has .movedto a. point I4 l forming theens1e Asa This information will appear on conductors 23 and 24 causing the antenna axis to align itself with the target, the voltages on conductors 23 and 24 being the up and down indicating voltages controlling the direction of rotation of the servomotor 50. The antenna has now rotated upward through an angle a in effect shifting the fore-and-aft reference axis 9 from coincidence with the line of flight |30|40 to a new position |3|-|4|. This upward rotation will cause the free-running pulley 53 to move downward, causing slack in the cable 54-54. The spring loaded drum 55 of gyroscope 56 will absorb this slack by its rotation, thereby disturbing the neutral position of the gyroscope suction orifice with respect to the gyroscopic positioned deilecting vane. Resulting from this movement, there appears on conductor 69 a voltage that is applied to terminal of the elevator servomotor 60 producing aV clockwise rotation of v the servo motorV arm 59, i, e., to the left. The

movement of arm 59 acts on the cable 13 operating over pulley 14 in such a manner as to'raise the elevator 15 and cause the missile toV travel upward'. Occurring simultaneously with the change ofthe missiles flight attitude is the action of the follow-up cable 54 acting so as to remove the vsuction orice displacement caused by the antenna movement. Because of the reversed connections to the gyroscope pick-off contacts, the planes upward movement displaces the gyroscope vorifice with respect` to the gyroscopic xed position of the deiiectng vane so as to maintain voltage on conductor 69 providing continuous clockwise torque on arm 59 of the servo 60. The antenna being afxed to the missile will be displaced from the target as the missile moves upward. The f antenna and radar sensing circuits detecting this displacement act so as to reverse the voltage in conductors 23 and 24, and the antenna moves ydownward as to reposition itself on the target.

This downward motion of the antenna displaces the gyroscope orice in a'direction as to attempt to provide a downward voltage on conductor '|0 and does provide this voltage when the orifice movement in this direction becomes greater relative to the displacement being providedin the opposite sense by the missiles changing motion upward. When the down voltage appears on conductor 'l0 applied to termina1 'l2 of the elevator servo 60, the arm '59 moves tothe right to its neutral position, thereby neutralizing the elevator 'l5 and also neutralizing the gyroscope 56 on its newly established stabilization axis ISI-|33 of Fig. 5. Resulting from the simultaneous movements of the antenna axis 3 9 and the missiles night path, the missile now travels along a course |3||33 while the antenna reference axis 9 coincides with the line-of-sight from missile to target |3||4|. The antenna axis has shifted through an angle a, Whereas the missile path` has shifted through an angle dependingupon the ratios set up in the control system. The Vchoice of this ratio is de-pendent upon the definite damp-l ing requirements associated with the particular type missile or airframe in use, and determination of the concise ratio for a specific type airframe will have to be made from an actual test flight of the type airframe in question. For example,'in test flights using this invention in a twin-engine aircraft of Beechcraft manufacture, it has been found that a ratio of 2.711 provides the Ymost eiiicient operation. Ratios are varied in the elevation *control system by varying the radialupositonnofgthe pulley 53 on the gear seg.-V

ment:52;and/or `also by'varying ,thelengthzofs the arm; Sirof .the elevatorgservo:60l',` Thus asthe; an;-

tenna--axis'shifts ,through anangl e a, the missile changes course -by anangleRtimes-c vWhere-R l is .the ratio selected:wherein selection of theA properrratiofforalspecic type-,airframe will pro-f vide :for that "airframe thel proper, corrections toguide-it-along an-interceptcourse -to apoint of impact with the selected target. Thus at any point alongV the iiightpatlr` I 3 I--I 33g the antenna` I will bear onthe target.4 For instance, at a point I32 thetarget has moved :to point kIl2,jand `the l antenna axis I32%IQZnloeingglgparallel WithV thev previously correctedlrorientation ISI-MI intersects the;targetipathwatpoint m2, the target`v location for missilezposition 132;; At point |33- I43'1target 'and missile.-;paths intersect, hence, the pointof contact-fand detonation'oi the previously-armed missile."-

Ini considering;-` the azimuth control of 'the missile-f referenceV Willlbe made to: Figs. 3 -and- 6.1 From'the pointo release of the missileirom the parent craft! 30, the missile Will-'have to travel to :some point .I 3 Iy AfWhereupon--the radar 'and vantenna sensing ,circuits fcangdetectangular vmovet-r ment of gtheftargct in tthefhorizontal plane.-U The.'

tween the missile gpath-l3ilellillfandfthe line fof sightiromsthe missiles `.presenteposition I 3l and the,;targets position ISI.' As-,f ag resultl of this angular displacement ,of the target withrespect tothe fore-rand-aft referenceaaxis, voltagesgwil-L appear on the conductors 25 and 2S Witlr such;

reverse.connected:igrroscoive 8h thereby dis.

placingthe gyroscope oricez in a directionso as, to producev a -lvoltage on conductor Sit- The conductor lSgconnects withthegcontact- Iilll which controls theiconnterclockwiserotation ,of the 90?. yokegBil-fof the proportional-roll trimv motor QI.` Thegrotatinroi-the90Q yoke iirallows the followup, cable;toaremoye theV gyroscope oriiice, displacement-of-gyroscoperl previously; placedV there as@ lfultof tthegantenna rotation. The rotation l,

oftherSQP-"yole-:SB also produces a slackA inl-:the cablingJi-'lf-Iilf Vwhich :is absorbed bythe rotation. ,of thefspringgloaded drum I t4 of the: conventionally-connected vertically stable gyroscope i iy'therotationgproducing a displacement of the gyroscopeA orificeandthus `causing-a voltage to appearon Ithe conductorfl I 4.: The-signal appear-- ingyon fconductor r I I 4 'produces a counter-clock- Wise,f1'otation1pf-the arm `IGS) of the,l aileron servo Hit.; Bvfmeans of theca-bles II'! and IBI, the

rotaticn -ofthe servoA arm |09'y imparts a mech-anical-actiontothe aileron yI I8k andrudder I23frespectively, causing; the missile to bank to the-right; Asa furtherresultof the rotation of thefzarm-I9, theffollowup vcable, It@ acts to partiallygremrove the previously placed prince displacement; in; they gyroscope I 65a, Asfthe missile hankstothe right;severaliactions occur inthe control ;elementszgsimultaneously. 1 Asa result; ofv

the reversed connectionsftocthe gyroscoperB-'I and the missiles change of v coursesto :the -right, the4 relative vorifice and; vane displacement thusf'produced tend'to maintain-the 4right controllingvolt-.. age to contact IO0I'='on; conductor -98Twhereasgthe relative displacement-- of the Aelementsgof j the conventionally-connected fgyroscopav I Uwtendrtoproduce a;left-'controlling voltagey -conductor@ I I3'in oppositionito the tendencyt in the loppositef.; sense-y produced .bythe action-of Cable I 03;? Ther antenna gis, bei-ng; shifted tofr the left at; this time;- inv'order Vto'continue bearing .on the: targets Thusl i the cable 35 producessa rotation yoiLtl'ije, dnumru displacing thefforice voff the :leyroscopeel nciently to counteractL the displacement mythe i 'oppositeesensegcaused bylfthe missiles changenti course. Simultaneously-,-,the-:missils :hangin attitude 'has y provided;'sufficientedisplacement to 13;. overridey the displacement in theigopposite isense, i by thef'shift -in `position of the..90\yole9 jgand; aq left control voltage appears oncondllatorfll whereupon'theaileronservomotor Ilihrotates f a clockwise direction to, :returnr its; arm :19% :andev the controlsurfaces-1 I 8 fand# I 2-3-1rlinkedmtheretmrintoaJ neutralposition'.V The followeupfcable.; 10335 acts e on the drum I nii-:to reestablish--equilibrium:

in the gyroscope m52@ Thus-hothrgyroscopeslf and H15- havel been;neutralized:I` aboutrzafinemf stabilization axisy ff and equilibrium@ agans'.; es -w tablished e while -the qfmissilef returns tozits fnew flight attitude andl :flies along; --itS:.1neWr-fcourse, I 3:-I-I 53 sincefthe smovementfoffthe farmiil 0 9 als lowed the rudderf'and'aileron rsurfacestozzreturnf toctheir neutra-1 positions.y Theyantennafifore. and-afty reference axis See-9? nowucoincides'; with q theline. of sight .IMF-|61 'fromthe missile1 to athw target now= atzpoint I 6l? Titus-fthe` antenna/:axis: hasbeen shifted throughfan anglezrwhereas thefV missile path Yhas shifted',througlnan'iangle de;- pendent upon fthe-ratiosgexisting inA ',theffazimnth i control system:v Itrfwill 4loefapparel-11mthatfthey dam-ping characteristics?. of the particular type a f missile or airframeffin use: mustfbe: .considerediin1 the.K selection'- of r*the `ratios yto vbe `:used .f-.infthe :f azimuth control unit asf fin1the l,elevation controli: unit'asy previouslyT ydescribed;`v Ratiosi-garecvaried inth-e azimuth control unit by, changing` theV radial jposition of the :pulleyaft ongthe tableau! and/or also byv vvarying they lengths of: the arms-:I ofthef'yoke. Imhof/the roll'trimmotoral ands. the. arm IIJS'ofthe aileron servo I It. Determina,- tion of the properfratio to be usedfforiazspecic typeairframe Will be made' from van actual-testi nightof the type airframe inquestiona-tle limits-s` ofthe ratio yto he used in generalffalli-ng yvitliinfzr therlimits as determinedfor the. elevation system previously-- Againv selection 'ofithe: proper.` ratio fora specific type airframer will providez `for :thatfl f airframe the proper ycorrections to guidefit:along.y

an intercept courseto the pointsoflimpactxwith'vv th'e target. Thus, in-the examplez depictedibyA Fig;- 6, it vcan loe-seen thatf'atany-pointyalonga-. the. flight path I3'I-I53; thefantennazwi'll [bear-l on the target. For instance,L at appointrISZ-,/the:

target has moved to-a'point lrandfthe antenna:A axis I zt-I 52- ibeingpparallel ,I'With' fthe previously; corrected orientation I3I--I6I intersects the. target'ipathv I @IL-m3F at `thepointl-l62i At` the` point ISS- |53 "the target-and the missile'rapaths; intersect, hence the pointof'contact and-detonar` tion of the previously: armed missile.

Treating the elevationu and] azimuthecontrolicircuitsrseparately is analogous to theg angular, resolution of the simultaneous effect-ofboth-cone` tici4 .i systems inta,I quadrature eects.. Conse-A quently, combining the two,feifects@producesfthe;v

ll simultaneous control actually provided inkthis invention. Referring to Fig. 7, it can be seen that the numbered points therein corresponding to identical numbered points in Figs. and 6 thus depict identical points. Hence, the path |48| 63 represents Vectorially the target path in the horizontal plane; Mil-|43, the target path in the vertical plane; ISI-|63, the corrected missile path in the horizontal plane; |3|-|43, the corrected missile path in the vertical plane; etc. Thus the path |40|93 is the vector summation of paths |40|43 and |40-I63, and represents the path of the target in space; whereas the path |3|;2|l3 is the vector summation of paths |3||43 and |3|-'|63 and represents the corrected path of the missile in space. Combination of the quadrature antenna beam directions |3||4| and |3||6| provide the antenna beam space direction |3||9|; and at any point along the flight path |3|-2D3, the antenna will bear on the target. For instance, at a point 282, the target has moved to a point |92, and the antenna axis 202-'-|92 being parallel with the previously corrected orientation |3 ||9| intersects the target path |40-203 at the'point |92. At the point |93-203, the space paths of the antenna and the missile intersect, hence, the point of contact and detonation of the previously armed missile.

The operation of the space reference gyroscope 56 Will be described more specifically with reference to Fig. 8 which is a cut-away View of the gyroscope 56 and other cooperating elements and in which corresponding numbers referto corresponding parts in the preferred embodiment of Fig. 3. The cable 54', which is connected to the free-rotating pulley 53 of the antenna gear segment 52, operates over the pulley 55 which is provided With spring loading due to the action of the spring |10. The spring loading thus produced delivers a torque to the pulley |1| which is rigidly aflixed to the shaft |12 and thereby produces a clockwise rotation of the shaft |12 when the cable 54' is payed out as by an upward shift of the fore-and-aft reference axis 9. The orifice positioning gear |13 is attached to a shaft whosev axis is coincident with the longitudinal axis |14--I14 of the gyroscope 56. rThis gear |13y meshes with the pinion |15 which is rigidly fixed to the shaft |12. Thus an upward motion of the cable 54 will cause clockwise rotation of the shaft |12 and pinion |15, thereby controlling a counterclockwise rotation of the gear |13. An air-tight slot |16 is provided in the end plate of the' gyroscope 56 to allow movement ofthe connecting pipe |11 leading to the Sylphon |18.` The'gyroscopic controlling elements include the 'suspension gimbals |8| in the vertical plane and |82 in the horizontal plane, suitable pivots |83 and |83V being 'provided at the intersection of the gimbal' |82 with the longitudinal axis |14-I14. Also mounted on the gimbal |82 at its' point ofinter-v section with the longitudinal axis |14|14l and perpendicular to that axis |14-I14 is the gyroscopic-positioned vane |84 covering one-half of the orifice |85 with all elements in a neutral position.` A rotor |86 is mounted on the gimbals |8| and |82, rotation being provided by suitable mechanical, electrical, or air devices. An uncaging device 6| operated by the AVC voltage appearing on conductor 44 allows movement of the gyroscope case with respect to the gyroscope elements |8|, |82, |84,'and |86 about an axis coincident with the longitudinal axis |14-|14 when the missile changes flight attitude in the vertical transverse plane.

The Sylphon |18 expands and contracts in accordance with the amount of suction'applied through the connecting pipe |11, the amount of suction being determined by the position of the vane |'84l with respect to the orice |85. Mechanical linkages are provided to selectively furnish voltage to the conductors 69 and 18, expansion of the Sylphon |18 causing contact |88 to move to the right completing the circuit from the battery contact 65 to the conductor 69, whereas contraction of the Sylphon |18 causes Contact |88 to move to the left completing the circuit from the battery contact 6| to the conductor 10. A small bleed hole |89 open to the atmosphere is provided in the Sylphon |18 allowing a small air intake, thereby permitting the Sylphon |18 to expand when the suction is substantially cut off by total coverage of the oriiice by the vane |84. The size of the bleed hole |89 is such as to provide an equilibrium condition with the oriiice |85 onehalf covered by the vane 84, wherein the contact 88 remains in a neutralposition at the center of its travel providing an open circuit from the battery contact 65 to either conductor 69 or 10. Thus a slight covering of the orifice |85 will cause expansion of the Sylphon |18 and completion of the circuit to conductor 69, Whereas a slight uncovering of the orifice |85 will cause contraction of the Sylphon |18 thereby completing the circuit to the conductor 10. A Vacuum source, preferably an external vacuum pitot tube in the airstream surrounding the missile, is connected to the case of the gyroscope 56 through the tubing 64.

Thus, in conjunction with the broad description of the pitch control of the missile, a paralleled description folio-ws, but more speciiically describing the actions taking place in the gyroscope 56 itself. In the problem taken up in reference to Fig. 5, the initial disturbance resulted from an antenna movement upward of a degrees, causing slack to appear in the cable 54. The slack is absorbed by clockwise rotation of the pulley 55. The clockwise rotation of the pulley 55 thus produces a counterclockwise rot-ation of the gear |13 thereby moving the orifice |85 downward to allowthe vane |84 to more completely cover the orifice |85. The Sylphon therefore expands and a voltage appears on conductor 69 producing a clockwise rotation of the arm 59 of the elevator servo 68 thereby raising the elevator 15 to cause the missile to travel upward, the follow-up cable. 54 acting so as to remove the displacement of the oriiice with respect to the vane |84. As the missile changes its attitude, the gyroscope case affixed to it also changes attitude thereby disturbing the relative position lof the orice |85 with respect to the gyroscopic fixed position of the vane |I84. This action causes the Voltage on conductor 69 to so remain. As the antenna moves down to counteract the effect of the upward moving missile, tension is induced in the cable 54 thereby Vdisplacing the nozzle opening |85 in a direction attempting to increase the suction. As increased suction is induced when the change of displacement in this sense becomes greater relative to the displacement of the vane |84 acting to decrease the suction as a result of the missiles upward change of direction. The increased suction in the pipe |10 causing contraction of the Sylphon |18, closes the battery circuit to conductor 10 thereby producing a counterclockwise rotation of arm 59, returning the arm 59 to its neutral position. The motion ofthe arm 59 acting on the cable 13 neutralized 1235 the elevator l5 `and' asfai result of its-actonr.on;v the follow-up cablell; the nozzle:A opening; |815.- has been displaced into` aneutralposition about` the.- newly established stabilizationlaxisgof the gyroscope 56. 5;.

The operation of the gyrosccpe'S-'l :isiclentical': with the described operation olgyroscope 56, although it willbe apparenttthat; thegyroscope 8l is provided for azimuth control, whereas the gyrosoope 56.' is providedzfor elevationacontrol. The verticallystable gyroscope, iBS-iis; connected -f in the conventional manner, and1itis-feltthat suficient prior art isfavalablesoiasfnotto war-r rantv a detailed explanationof itsoperation.,

Fig. 9 shows analternateformfofthe proposed invention wherein.; thersolid .1 connectingi'linesf-inidicate electrical connections-,1 and theibroken-:connesting lines indicate mechanicallinkageszand; wherein, for easeof identification; thefnurnberK parts are 200. units largeriinnumericalvaluethan N the corresponding; parts of'ithe'preferred block-1 diagram of Fig. 2. The..foregoingdescriptionzof. the preferred embodiment enables elimination of detail in the block diagramvof'z-Fgr!) for-Clare ity and ease in understandinggthis alternate form. ,25 The arrangement:ofthe'parts of Eig. gisnsinrli`` lar to the arrangement .of Fig. 2.' Thegdeviation appears in thev connections betweentheradar. unit' Zit, the gyroscope pick-toits', andthe several servomotors. The radar equipment 2.13; which is understood-to: include all detailedelementsl'of the radar equipment of Fig. 3; providesazimuth control volt-ages to the proportional. rol-1* trimmotor Se? whichy affects the stableverticalIg-yro-- scope 3&5 to operate the'remainderoithelele ments in the azimuthrsystem; i e., tlieAaileron` and rudder servomotor (i,I aileron 3 i813 and rudder and inaddition, provides-ffollloW-up to the space reference gyroscope 281. The-output` from the'pick-oil means of gyroscope flcontrols the antenna azimuth A servomotor 2 83 fto" position Y the antenna 2i? in azimuth.

The radar system Zl'also provides elevation control voltages to the elevator servo-ZEW- to'control the elevatorl 2'15' and provide fol-lovvup` for the space reference gyroscope 256, theoutputof` which controls the antenna` 2H in elevatiorrby` means of elevation sen/omotor4 25d:

Thus the missile and the antenna are provided' with means forcontrol in both azimuth and elevation.

The inventiondescribed herein may be manufactured and used by v or for the Government of" the United Statesof Americafor. governmental purposes Without the. payment' of. any. royalties` thereon or therefor.

What is claimed is:

1. A movable object having control surfaces` including. azimuth and elevation control surfaces, radar means including an vantenna carried. by said movable object for providing sensing.. voltages indicative of the direction orthereceived.` Waves, means responsive to the outputr of. said radar means to control saidantenna inazimuth and elevation, a irst reverse-connected gylof. scope having an adjustable stabilizationxaxisfand. pick-on" means to controlsaid"elevation.controlsuriaces, said stabilization axis beingcontrolledy by the action in elevation of said antenna andfurther controlled by the, action oisaidelevation control surfaces, a controlfmeans. a secondreverse-connected gyroscope having an=adjustable stabilization axis and-pick-oi meanstogcontrol said control means, said stabilizationraxis:beingE tennaf, andn. further. controlled by; said` controle meanseand-a stablea vertical gylosoopel; with` an 1. adjustableffstabilization:axis Vand pick-oftmeans. to: controll said.: azimuth.. control surfaces; said.-V stabilization axis being; controlled by said control means, and furthercontrolled f by; the` action `of said-zazimuth control surfaces, whereby thev over:- l all r control :including the correction provided b5" thee reverse-connected: gyroscopes directs? saidy movable;` obj ectalong. a-n intercept course-ftd as; target detected vby.said fradar f means.-

2r Anmovable object having), controls surfaces,- inc-ludingf azimuth and? elevation control surfaces, radar meansfincludi-ng an antenna .carriedw-by said a object for providing sensingzvoltagesindicativefo the-:direction q of:j the `received. Waves; rst.- means responsiveeto;thefoutput-lof said radar, means to'l control-said: antenna in azimuth. andelevation,v second means to controlfsaid'felevation.control. surfaces.. a rst reverse-connected gyroscope havingaan adjustable stabilization` axis f and pick-'oir means,` .to control l said elevation .control surf acesthrough :said second controL-means said stabiliza-` y tionaaxisfbeing controlled bysthe action lin feleva-V 1 tion. of f. said ...antennal and further.' controlled-fbx?,v

f means: .tocontrolsaidv third :control means-said.l

stabilization a-X-is beingg controlled ,by fthe :action in fazimuthzof '-said-antennafand further.controlled.vt byrsaidwthirdcontrol' means;- fourthmeans. tacone-I trol r saidsazirnuth control surfaces,` and (a: stablermitlr control surfaces through'I saidffourth 'L con+ trol lmeanssaid stabilizationfaxis being;controlled-- by said' third control: means f, and" further" cone trolled by th'efacton lof csaid azimuthcontrol 'sure faces=tlflroughsaid f'fourth -controlmeans; Whereby-tlie-overa1l control includingtthecorrection provided'fby tlief reversa-connectedgyroscopesdi; rects the movable objectfalong `an intercept:course` to' aA target detected'by said" radar means.-`

3;t Trie-apparatus described" in' claim 2 whereinthe first; second,v third andfourtli control means are servomotors.

4.- The apparatus described in claim 2 whereinv the iirst;A second and fourth control means are servomotors, and the third control means is a proportional roll trim motor.

5'; A movable objecthaving control surfaces includingrudder, elevator and aileron. control surfaces, radar meansincluding an antenna carried by said movable object for providing sensing voltagesindicative of the. directionof the received wavesdirst means responsive to the output ofy saidfradar. meansto control said antenna, in. azimutl'il and elevation, second means. to control said; elevator surfaces,.,a .rst reverse-,connected gyroscope havingan adjustable stabilization axis and pick-01T means to control said elevator surfaces Ythrough said second control means said4 stabilizationaxisj beingu controlled by the action in elevation of .said'antenna and further controlledr by the actionof saidelevator surfaces through said second control means, athird control means, a secondreverse-connectedgyroscope having anA adjustable stabilization axis and. pick-off; means.. to. control said third control .meanssaid stabilizationlaxis ,beingcontrolledby the action. in` azimuth of. said antenna Iand' further. controlledby.

ntroued by the action in azimuthv said an- 75..-saidthird-.control means, fourth controlimeansta 15 controlisaid aileron and rudder surfaces, Aandr a stable -vertical'vg'yroscope with an adjustablestabiliz'ation axis and pick-off means to control said aileron and rudder surfaces through said fourth control means said stabilization axis being controlled by said third control means and further controlled by the action of said aileron and rudder surfaces through said fourth control means, whereby the overall control including the correction provided by the reverse-connected gyroscopes directs the movable object along an intercept course to a target detected by said radar means.

A 6. The apparatus as described in claim wherein the first, second. third and 'fourth' control means are servomotors.

7.*The apparatus described in claim 5 wherein ythe first, second and fourth control means are means responsive to the output of said radar; means, asecond reverse-connected gyroscope having an adjustable stabilization axis'and pickoff means to control said antenna in azimuth said means and further controlled by the action in elevation of said antenna, and a stable vertical gyroscope having an adjustable stabilization axis and pick-off means'to control said azimuth-control surfaces said stabilization axis being controlled by said control means and further controlled by the action of said azimuth control surfaces, Whereby the overall control including the correction provided by the reverse connected gyroscopes directs said movable object along an intercept course to a target detected by said radarv means.

9. A movable object having control surfaces including azimuth and elevation control surfaces, radar means including an antenna carried by said movable object for providing sensing voltages indicative of the direction of the received waves, first means to control said antenna in elevation, second means responsive to the output of said radar means to control said elevation control surfaces, rst reverse-connected gyroscope having an adjustable stabilization axis and pickoff means to control said iirst control means said stabilization axis being controlled by said second means and further controlled by the action in elevation of said antenna, third means to control said antenna in azimuth, fourth means responsive to the output of said radar means, a secondv reverse-connected gyroscope having an adjustable stabilization axis and pick-off means to control said third control means said stabilization axis being controlled by said fourthmeans and further controlled by the action in azimuth of I said antenna, fifth means to control said azimuth control surfaces, and a stable vertical gyroscope having an adjustable stabilization axis and pick-off means to control said azimuth control surfacesthrough said fifth control means said stabilization axis being controlled by said fourth stabilization axis being controlled by said control r'- tion of said azimuth control surfaces, whereby the overall control including the correction lprovided by the reverse-connected gyroscopes directs the movable object along an intercept course to a target detected by said radar means.

10. The apparatus described in claim 9 wherein the iirst, second, third,vfourth and fifth control means are servomotors.

11. The apparatus described in claim 9 wherein the lfirst, second, third and fth control means are servomotors, and the fourth control means is a proportional roll trim motor.

12. A movable object having control surfaces including rudder, elevator and aileron control surfaces, radar means including an antenna carried by said movable object for providing sensing voltagesy indicative of the direction ofthe received waves', first means to control said antenna in elevation, second means responsive to the output of said radar means to control said elevator surfaces, rst reverse-connected gyroscope having an adjustable stabilization axis and pick-off means to control said first control means said stabilization axis being controlled by said second means and further controlled by the action in elevation of said antenna, third means to control said antenna in azimuth, fourth means responsive to the output of said radar means, a second reverse-connected gyroscope having an adjustablestabilization axis and pick-off means to control said third control means said stabilization axis being controlled by said fourth means and further controlled by the action in azimuth of said antenna, fifth means to control said rudder and aileron surfaces, and a stable vertical gyro- I scope having an adjustable stabilization axis and pick-olf means to control said rudder and aileron surfaces through said fifth control means said stabilization axis being controlled by said fourth control Lmeans and further controlled by the movement of said rudder and aileron surfaces, whereby the overall -control including the correction provided by the reverse-connected gyroscopes directs the movable object along an intercept course to a target detected by said radar means.

13. The apparatus described in claim 12 wherein the first, second, third, fourth and fifth control means are servomotors.

14. The apparatus described in claim 12 wherein the iirst, second, third and fifth control means are servomotors, and the fourth control means is a proportional roll trim motor.

15. A movable object having control surfaces including azimuth and elevational control surfaces, radar means including an antenna carried by said movable object for providing elevation and azimuth voltages indicative of the position of the source of received waves, a stable vertical gyrosco'pe for controlling said azimuth control surfaces, control means for controlling said stable vertical gyroscope, a first reverse-connected gyroscope cooperating with the elevation output voltages of said radar means for controlling said elevation control surfaces and for controlling said I antenna in elevation, a second reverse-connected lncluding azimuth and elevation control surfaces, radar means including an antenna carried by said movable object for providing elevation and azimuth voltages indicative of the position of the source of received Waves, rst means for operating said azimuth control surfaces, a stable vertical gyroscope for controlling said first means, second means for controlling said stable vertical gyroscope, third means for controlling said elevation control surfaces, fourth means for controlling said antenna in elevation, a first reverseconnected gyroscope cooperating with the elevation output voltages of said radar means for controlling said third and fourth means, fth means for controlling said antenna in azimuth, a second reverse-connected gyroscope cooperating with the azimuth output voltage of said radar means for controlling said second and fifth means, whereby the overall control including the correction provided by the reverse-connected gyroscopes directs said movable object along an intercept course to a target detected by said radar means.

17. The apparatus as described in claim 16 wherein the first, second, third, fourth and fth means are servomotors.

18. The apparatus described in claim 16 wherein the rst, third, fourth and fifth means are servomotors, and the second means is a proportional roll trim motor.

19. .A movable object having control surfaces including rudder, elevator and aileron control surfaces, radar means including an antenna carried by said movable object for providing elevation and azimuth voltages indicative of the position of the source of received Waves, rst means for operating said rudder and aileron control surfaces, a stable vertical gyroscope for con-f' trolling said rst means, second means for controlling said stable vertical gyroscope, third means for controlling said elevator control surfaces, fourth means for controlling said antenna in elevation, a rst reverse-connected gyroscope cooperating With the elevation output voltages of said radar means for controlling said third and fourth means, a -fth means for controlling said antenna in azimuth, a second reverse-connected gyroscope cooperating with the azimuth output voltages of said radar means for controlling said second and fifth means, whereby the overall control including the correction provided by the reverse-connected gyroscopes directs said movable object along an intercept course to a, target detected by said radar means.

20. The apparatus as described in claim 19 wherein the rst, second, third, fourth and fth means are servomotors.

21. The apparatus as described in claim 19I wherein said first, third, fourth and fifth means are servomotors, and the second means is a proportional roll trim motor.

EARL C. SPARKS, JR. MOULTON B. TAYLOR.

REFERENCES CITED The following references are of record in the Certificater of Correction Patent No. 2,512,693 June 27 1950 EARL C. SPARKS, Jn., ET AL. It is hereby certied that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 7, line 38, for intecept read intercept; line 52, for missble read missile; and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the crise in the Patent OIce.

Signed and sealed this 17th day of October, A. D. 1950.

THOMAS F. MURPHY,

Assistant ommissioner of Patents.

Certificater of Correction Patent No. 2,512,693 June 27, 1950"" EARL C. SPARKS, Jn., ET AL. It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 7, line 38, for ntecept read lintercept; line 52, for "mssib1e read miss/ile; and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Oice.

Signed and sealed this 17th day of October, A. D. 1950.

THOMAS F. MURPHY, c

Assistant 00m/missione?? of Patents. 

